Two-cycle internal combustion engine



Jul 25, 1933.

c. G. CURTIS ET AL 1,919,829

TWO-CYCLE INTERNAL COMBUSTION ENGINE Filed Oct. 1, 1951 2 sheets-sheet 1TWN y 1933. v c. G. CURTIS ETIAL ,919,829

TWO-CYCLE INTERNAL COMBUSTION ENGINE Filed 001;. 1, 193i 2 Sheets-Sheet2 I c l 5 3 I day I patented July 25, 11933 inten CHLES Gr. CURTIS, OFNEW YORK, AND EARLE R. NEWTOIT, @313 JAMAICA,'NEW YQRK TWO-CYCIJEINTERNAL COMBUSTION ENGINE Application filed October 1, 1931. Serial No.566,244.

This invention relates to the scavenging and supercharging of two cycleinternal combustion engine cylinders of the portscavenged type. Itapplies particularly to long stroke engines in which the path of thescavenging air through .the cylinder is long.

The invention provides for a scavenging system comprising exhaust portsarranged on one side of the cylinder near the end of the stroke remotefrom the combustion end,

and air inlet ports arranged one above the other in two transverseplanes,.near the same end, and generally oppositely disposed to theexhaust ports. The air inlet ports are characterized in that those ineach transverse plane comprise oppositely disposed ports turned backtoward the inlet side of the cylinder, like those described and claimedin applicants earlier United States Patents, Nos. 1,777,827 and1,780,175.

The invention is applicable to both single acting and double acting twocycle engines, with or without inlet valves or exhaust valves.

The object of the invention is to improve the scavenging efficiency oftwo cycle engine cylinders which utilize inlet-ports arranged in twotransverse planes. The features and advantage of the invention appear inthe description which follows and in the drawings. The invention,however, is not limited to the specific arrangements illustrated.

' Figure 1 is a sectional elevation of, an engine to which the inventionis applicable The engine shown is a double acting engine with air inletports oppositely disposed to the exhaust port arranged in threetransverse planes. The air inlet ports in the intermediate plane arearranged to serve each end of the double acting cylinder alternately sothat air-inlet ports in two planes are in use during. the scavenging ofeach end of the cylinder.

Fig. 2 is a transverse, somewhat diagrammatic section through the airinlet ports in one transverse plane in accordance. with the invention.In the illustrated embodiment the inlet ports in each transverse planeare similar, that is, corresponding ports in the two planes are alike,hence only one transverse section is shown. Figs. 3, 4, 5 and 6 arediagramsshowing longitudinal sections through the various ports in. oneplane and showing a changing obliquity of the ports to the longitudinalaxis of the cylinder in accordance with one embodiment of the invention.

Heretofore inlet-ports arranged in two planes have used either radialports or ports turned toward the exhaust port side of the cylinder andthese arrangements do not givegood scavenging efiiciency although theydo give a supercharge to the cylinder. By directing the ports in eachplane back toward the inlet side of the cylinder the same superchargeeffect is obtained and the scavenging efficiency is very greatlyimproved.

In carrying out the invention we provide a two stroke internalcombustion' engine 7 comprising a cylinder 1, a reciprocating piston 2,exhaust ports 3, arranged in one side of the cylinder wall near the endof the stroke remote from the combustion end, and sets of air inletports 4' and 5 arranged in 7 two planes near the same end of the strokein that part of the arc of circumference not occupied-by the exhaustports, that is, in that part of the cylinder wall generally op positethe exhaust ports.

In the drawings the sets of-dnlet ports 4 and 5 in each transverse planeare similar, that is, corresponding'ports in the two planes are alike.They have the same angles, the

same height, the same width and are in the 35 same longitudinal plane.However, the ports in the two planes may be dissimilar, that is, theports in one plane may .difier in size, angle or location fromthe portsin the other p ane, provided each plane comprises 9% oppositely disposedports turned back toward the inlet side of the cylinder. The ports ineach plane are shown divided into two groups, fourports to each group.They are designated 4 4 4 4 4 4 4,, 4 and 5 5 5,, 5 5 5,, 5 5 and arearranged symmetrically about the center line 6 and turned back towardthe inlet side of the cylinder. The air-streams from the ports 4 to 4inclusive oppose the streams from the ports 4 to 4 inclusive. Similarlythe two groups of ports in plane or set 5 oppose each other. The middleports 4 and 4 are steeply oblique to the" longitudinal axis of thecylinder and the end ports 4 and 4 are of lesser angle. The same is trueof the ports in plane or set 5. This port arrangement prevents theincoming air from flowing transversely, or directly, across the cylinderto the exhaust ports and causes it to flow in a more or lesslongitudinal direction on the inlet port side of the cylinder to thecylinder cover and down the exhaust port side of the cylinder to theexhaust.

The operation of the two stroke cycle engine, having air inlet portsarranged in two transverse planes iswell known and such engines are incommon practice, and since the embodying of this invention in thatengine does not in any way modify the cycle of operations it need not bedescribed here. What we claim as new and desire to secure by'lliettersPatent of the United States isf 1. A two-cycle internal combustionengine comprising a cylinder, exhaust ports and air inlet ports arrangedin that end of the cylinder wall remote from the combustion end, theexhaust ports on one side and the air inlet ports on the other, said airinlet ports arranged in two transverse planes, the air inlet ports ineach of the said planes comprising oppositely disposed ports turned backtoward the inlet side of the cylinder wall so arranged that the airstreams issuing from them come together as opposing streams and set up aflow toward the combustion end of the cylinder on the inlet side.

2. A double-acting two-cycle internal combustion engine comprising acylinder, ex-

amaze haust ports and air inlet ports arranged in the cylinder remotefrom the combustion end, exhaust ports on one side and the air inletports on the other, said air inlet ports arranged in three transverseplanes, the air inlet ports in each of said planes comprising oppositelydisposed ports turned back toward the inlet side of the cylinder wall,the ports in the middle plane serving both ends of the double-actingcylinder alternately.

3. A two-cycle internal combustion engine comprising a cylinder, exhaustports in one side ofthe cylinder wall and remote from the combustionend, air inlet ports arranged generally opposite the exhaust ports intwo planes or sets, the ports in the middle portion of each set beingoblique to the longitudinal axis of, the cylinder, the ports in the endportions of each set being less steeply oblique and turned back towardthe inlet side of the cylinder wall.

4. An engine according to claim 1 further characterized by the ports inthe two planes being similar in that there are the same number of portsin each plane and corresponding ports in the two transverse planes arein the same longitudinal plane, have the same angles and are of the samesize.

5. An engine according to claim 1 wherein the ports in the uppertransverse plane reach higher up in the cylinder than the exhaust ports,and further comprising valve-means controlling said upper inlet-portsarranged to stay open after the exhaust ports are closed.

" CHARLES G. CURTIS.

EARLE R NEWTON.

